ML20100N884

Supplemental Final Deficiency Rept,Item 111 Re Design Deficiency on RHR Reservoir Freeze Over.Methods for Adding Heat to RHR Reservoir Clarified

ML20100N884
Person / Time
Site:	Fermi
Issue date:	11/30/1984
From:	Jens W DETROIT EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
111, EF2-70219, NUDOCS 8412130534
Download: ML20100N884 (2)

Text

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Wayne H. Je O Eco President

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e - , Nuclear Operataxis 6400 h Dxie Highway ISAF% Newport, Mchigan 48166 IQUI l (sis) ses 4tso November 30, 1984 EF2-70219 Mr. James G. Keppler Regional Administrator Region III.

U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Reference:

(1) Fermi 2 NRC Docket No. 50-341 (2) Letter, W. H. Jens to J. G. Keppler, July 5, 1984, EF2-69272

Subject:

Clarification of Final Report of 10CFR50.55(e)

Item 111, " Design Deficiency on the RHR Reservoir Freeze Over" Reference 2 provided Detroit Edison's final report on 10CFR50.55(e) Item 111, " Design Deficiency on the RHR Reservoir Freeze Over". This letter provides clarification of the methods which will be used to add heat to the RHR reservoir.

During normal power operation of the plant, heat will be added to the reservoir through equipment surveillance testing and suppression pool cooling. This heat is expected to be sufficient to maintain the RHR reservoir temperature above 43*F during a normal winter. In the unlikely event

'that supplemental heating of the reservoir is needed, the EECW system would be operated. During an outage following power operation, decay heat from the reactor will add sufficient heat to the reservoir to maintain its temperature above 43*F during the coldest postulated winters.

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Mr. James G. Keepler November 30, 1984 EF2-70219 Page 2 For the current winter, reactor decay heat and plant operating heat loads may not be sufficient to maintain the reservoir temperature above 43*F. Therefore, Detroit Edison may use the emergency diesel generators (EDG's) as a supple-mental method for. heating the reservoir. Furthermore, Detroit Edison will operate only one of the four EDG's at a time to add heat to the reservoir. This method for heating the reservoir will be coordinated with the surveillance runs and other testing of the EDG's. This will minimize addition-al interaction between onsite and offsite sources of AC power. This practice will be discontinued prior to exceeding 5% power.

If you have any questions concerning this matter, please contact Mr. Lewis Bregni, (313) 586-5083.

Sincerely,

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cc Mr. P. M. Byron exi -

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Mr. R. C. DeYoung Mr. R. C. Knop \d Mr. M. D. Lynch USNRC, Document Control Desk Washington, D.C. 20555 i

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